Use reactive caching for 3rd party REST calls made by Jira request services

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JiraService model contains methods that make rest calls to jira api like jira_projects, close_issue, create_cross_reference_note, etc. These are better suited into a service class under app/services rather than the JiraService model itself, this is going to be addressed in #219204 (closed)

Given that we are calling Jira REST api from GraphQL, the GraphQL request has to wait for a response from Jira, so we should consider using reactive caching for that: https://docs.gitlab.com/ee/development/reactive_caching.html#when-to-use